Generally all higher powered guns tear themselves apart. The force exerted on a barrel when launching a projectile exists with traditional propellant as well. IIRC most large guns fire somewhere in th hundreds or thousands of times before major maintenance is needed, such as replacing a barrel. From an engineering stand point, you're trading off a number of attributes, one of which is use before maintenance; it appears to be regularly worthwhile to have a lighter, more powerful gun at the expense of life time. Formula One engines make a similar trade off. While I don't have any links on hand, from my readings here most projections for the rail gun were within this viable hundreds/thousands of shots range. Even if they weren't, given that their maximum range far exceeds ship board traditional guns, an argument could be made to compare the maximum number of rail gun shots before major maintenance should be compared against ship borne missiles, further lowering the requirement before they're deemed worthwhile.